Tablet coating composition

ABSTRACT

A tablet coating composition including a mixture of (a) sodium alginate and (b) a polyvinylpyrrolidone-vinyl acetate copolymer, and, optionally, (c) hydroxypropylmethyl cellulose, and/or hydroxypropyl cellulose.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to tablet coating compositions, and, moreparticularly, to such composition having an advantageous combination ofphysical properties which is a mixture in predetermined proportions ofsodium alginate and a polyvinylpyrrolidone-vinyl acetate copolymer.

[0003] 2. Description of the Prior Art

[0004] Hydroxymethyl cellulose is a good film former; however, its filmsare brittle, opaque and non-slippery. Accordingly, it is desired toprovide new and improved tablet coating compositions.

SUMMARY OF THE INVENTION

[0005] What is described herein is a tablet coating composition whichincludes a mixture of (a) sodium alginate and (b) apolyvinylpyrrolidone-vinyl acetate copolymer, and, optionally, (c)hydroxypropylmethyl cellulose, and/or hydroxypropyl cellulose.

[0006] This composition provides the tablet with a predetermined degreeof luster, strength, smoothness, slipperiness, color, modified releaseand ease of polishing.

[0007] In the preferred form of the invention, composition (b) includesby weight, 60-80% vinylpyrrolidone and 20-40% vinyl acetate; preferablythe composition has a K-value of about 25 to 34, calculated from itskinematic viscosity on a 1% aqueous solution.

[0008] Most preferably, the composition comprises, by weight, (a)10-98%, (b) 2-20%, and (c) 0-88%.

[0009] Application formulations of the composition of the inventioninclude a medicament, and/or a nutritional supplements.

DETAILED DESCRIPTION OF THE INVENTION

[0010] In this invention, tablets are coated with a predeterminedmixture of (a) sodium alginate and (b) a polyvinylpyrrolidone-vinylacetate copolymer, (Plasdone® S-630, International Specialty Products,Inc.), optionally with hydroxypropylmethyl cellulose, and/orhydroxypropyl cellulose.

[0011] Experimental

[0012] 1. Process/Composition:

[0013] Aqueous solutions of sodium alginates (Manucol LD, 5 cps orKeltone LV, 50 cps), and Plasdone® S-630, and color lakes, were sprayedonto placebo tablets* in a Glatt fluid-bed Wurster coater. The coatedtablets were characterized by their weight gain, and, subjectively, forcoating uniformity, lustrousness, and slipperiness/tackiness whenexposed to aqueous fluids.

[0014] * Placebo (lactose) tablets from Korsch Processing laboratorywere convex tablets (7.5 mm diameter; average thickness 5.6 mm), and theaverage tablet weight was 201.3 mg.

[0015] 2. Fluid bed conditions:

[0016] Glatt fluid-bed coater with Wurster adapter and plate B.

[0017] Batch size 400 g.

[0018] Spray rate: 10 g/min

[0019] Atomization pressure: 3 bar.

[0020] Drying air temperature: 60° C.

[0021] Flap: 35% open.

[0022] 3. Coating Procedure and Results:

[0023] Examples 1 and 2 were solutions of 10% Manucol LD with andwithout 2% by weight of Plasdone® S-630; 1000 ml of each were sprayedonto 400 g placebo tablets. The presence of the S-630 polymer in themixture gave the coated tablets a superior feeling of slipperiness.

[0024] Examples 2 and 4 were prepared similarly as in Examples 1 and 2;however, with the addition of 0.5% Yellow lake to allow for betterevaluation of coating uniformity. An increase in luster was observed inS-630 containing coated tablets.

[0025] Examples 5 and 6 were prepared with Keltone LV with and withoutS-630. These solutions were prepared with Keltone LV at a concentrationof 5.43% to maintain the viscosity of the solution at an acceptablelevel, and with 0.36% Red lake. Tablets coated with the Keltone/S-630solution gave a lustrous, slippery coating when wet. Tablets coated withKeltone only produced an uneven coating, which was unacceptable, andtackiness, rather than slipperiness, when wet. TABLE Wt. Ex. Plasdone ®Increase Physical Properties of No. Alginate, (%) S-630 (%) Lake, (%)(%) Coating 1 Manucol LD, 10 2 — 3.00 Lustrous, slippery coating 2Manucol LD, 10 — — 3.52 Lustrous, tacky then slippery coating 3 ManucolLD, 10 2 Yellow, 3.93 Lustrous, slippery 0.5 coating 4 Manucol LD, 10 —Yellow, 3.27 Borderline lustrous, 0.5 slippery coating 5 Keltone LV,5.43  0.72 Red, 0.36 7.05 Lustrous, slippery coating 6 Keltone LV, 5.43— Red, 0.36 2.19 Uneven coating, tacky

[0026] The results show that aqueous solutions of the tablet coatingcompositions of the invention comprising: (a) sodium alginate and (b)polyvinyl pyrrolidone (PVP)-vinyl acetate (VA) copolymer (Plasdone®S-630, 60% PVP, 30% VA, by wt.) have a lowered viscosity* where it makesthem easy to spray, even at a solids contents of 20%. These compositionsproduce a superior coating when compared to each of the ingredientsalone. If desired, (c) hydroxymethyl cellulose may be included in thecomposition in suitable amounts. Application formulations of thecomposition also may include a medicament and/or nutritional supplement.

[0027] While the invention has been described with particular referenceto certain embodiments thereof, it will be understood that changes andmodifications may be made which are within the skill of the art.Accordingly, it is intended to be bound only by the following claims, inwhich:

What is claimed is:
 1. A tablet coating composition comprising a mixtureof (a) sodium alginate, and (b) polyvinylpyrrolidone-vinyl acetatecopolymer, and, optionally, (c) hydroxypropylmethyl cellulose, and/orhydroxypropyl cellulose.
 2. A composition according to claim 1 having apredetermined degree of luster, strength, smoothness, slipperiness,color, modified release and ease of polishing.
 3. A compositionaccording to claim 1 wherein (b) comprises, by weight, 60-80%vinylpyrrolidone and 20-40% vinyl acetate, and has a K-value of about 25to 34, calculated from its kinematic viscosity on a 1% aqueous solution.4. A composition according to claim 1 comprising, by weight, (a) is10-98%, (b) is 2-20% and (c) is 0-88%.
 5. A composition according toclaim 1 including a medicament and/or a nutritional supplement.